Remove edge loop from selection in 2.8
You cannot select loops by double-clicking Shift+LMB in default Blender's 2.80 keymap. The hotkey for selecting edge loops in 2.80 is Alt+LMB by default. If you wish to add to the selection or subtract from it something that is already selected you hold Shift while using Alt+LMB. 

So the answer to your question is: 

When you select a few loops with Shift+Alt+LMB click, you can deselect them the same way clicking LMB while holding Shift+Alt on a loop that is already selected.